[Git][ghc/ghc][wip/ghc-9.4.5-backports] Fix void-arg-adding mechanism for worker/wrapper
Zubin (@wz1000)
gitlab at gitlab.haskell.org
Tue Apr 11 06:24:08 UTC 2023
Zubin pushed to branch wip/ghc-9.4.5-backports at Glasgow Haskell Compiler / GHC
Commits:
aad62f1f by Simon Peyton Jones at 2023-04-11T11:50:34+05:30
Fix void-arg-adding mechanism for worker/wrapper
As #22725 shows, in worker/wrapper we must add the void argument
/last/, not first. See GHC.Core.Opt.WorkWrap.Utils
Note [Worker/wrapper needs to add void arg last].
That led me to to study GHC.Core.Opt.SpecConstr
Note [SpecConstr needs to add void args first] which suggests the
opposite! And indeed I think it's the other way round for SpecConstr
-- or more precisely the void arg must precede the "extra_bndrs".
That led me to some refactoring of GHC.Core.Opt.SpecConstr.calcSpecInfo.
(cherry picked from commit 964284fcab6e27fe2fa5c279ea008551cbc15dbb)
- - - - -
7 changed files:
- compiler/GHC/Core/Opt/SpecConstr.hs
- compiler/GHC/Core/Opt/WorkWrap/Utils.hs
- compiler/GHC/Core/Utils.hs
- testsuite/tests/simplCore/should_compile/T13143.stderr
- testsuite/tests/simplCore/should_compile/T18328.stderr
- + testsuite/tests/simplCore/should_compile/T22725.hs
- testsuite/tests/simplCore/should_compile/all.T
Changes:
=====================================
compiler/GHC/Core/Opt/SpecConstr.hs
=====================================
@@ -45,6 +45,7 @@ import GHC.Unit.Module.ModGuts
import GHC.Types.Literal ( litIsLifted )
import GHC.Types.Id
+import GHC.Types.Id.Make ( voidArgId, voidPrimId )
import GHC.Types.Var.Env
import GHC.Types.Var.Set
import GHC.Types.Name
@@ -1741,24 +1742,13 @@ spec_one env fn arg_bndrs body (call_pat, rule_number)
-- return ()
-- And build the results
- ; let spec_body_ty = exprType spec_body
- (spec_lam_args1, spec_sig, spec_arity1, spec_join_arity1)
- = calcSpecInfo fn call_pat extra_bndrs
- -- Annotate the variables with the strictness information from
- -- the function (see Note [Strictness information in worker binders])
- add_void_arg = needsVoidWorkerArg fn arg_bndrs spec_lam_args1
- (spec_lam_args, spec_call_args, spec_arity, spec_join_arity)
- | add_void_arg
- -- See Note [SpecConst needs to add void args first]
- , (spec_lam_args, spec_call_args, _) <- addVoidWorkerArg spec_lam_args1 []
- -- needsVoidWorkerArg: usual w/w hack to avoid generating
- -- a spec_rhs of unlifted type and no args.
- , !spec_arity <- spec_arity1 + 1
- , !spec_join_arity <- fmap (+ 1) spec_join_arity1
- = (spec_lam_args, spec_call_args, spec_arity, spec_join_arity)
- | otherwise
- = (spec_lam_args1, spec_lam_args1, spec_arity1, spec_join_arity1)
+ ; let spec_body_ty = exprType spec_body
+ (spec_lam_args, spec_call_args, spec_sig)
+ = calcSpecInfo fn arg_bndrs call_pat extra_bndrs
+ spec_arity = count isId spec_lam_args
+ spec_join_arity | isJoinId fn = Just (length spec_call_args)
+ | otherwise = Nothing
spec_id = asWorkerLikeId $
mkLocalId spec_name Many
(mkLamTypes spec_lam_args spec_body_ty)
@@ -1768,13 +1758,9 @@ spec_one env fn arg_bndrs body (call_pat, rule_number)
`setIdArity` spec_arity
`asJoinId_maybe` spec_join_arity
- -- Conditionally use result of new worker-wrapper transform
- spec_rhs = mkLams spec_lam_args (mkSeqs cbv_args spec_body_ty spec_body)
- rule_rhs = mkVarApps (Var spec_id) $
- -- This will give us all the arguments we quantify over
- -- in the rule plus the void argument if present
- -- since `length(qvars) + void + length(extra_bndrs) = length spec_call_args`
- dropTail (length extra_bndrs) spec_call_args
+ -- Conditionally use result of new worker-wrapper transform
+ spec_rhs = mkLams spec_lam_args (mkSeqs cbv_args spec_body_ty spec_body)
+ rule_rhs = mkVarApps (Var spec_id) spec_call_args
inline_act = idInlineActivation fn
this_mod = sc_module env
rule = mkRule this_mod True {- Auto -} True {- Local -}
@@ -1814,64 +1800,122 @@ mkSeqs seqees res_ty rhs =
= rhs
-{- Note [SpecConst needs to add void args first]
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+{- Note [SpecConstr void argument insertion]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Consider a function
+ f :: Bool -> forall t. blah
f start @t = e
We want to specialize for a partially applied call `f True`.
See also Note [SpecConstr call patterns], second Wrinkle.
Naively we would expect to get
+ $sf :: forall t. blah
$sf @t = $se
RULE: f True = $sf
-The specialized function only takes a single type argument
-so we add a void argument to prevent it from turning into
-a thunk. See Note [Protecting the last value argument] for details
-why. Normally we would add the void argument after the
-type argument giving us:
+The specialized function only takes a single type argument so we add a
+void argument to prevent it from turning into a thunk. See Note
+[Protecting the last value argument] for details why. Normally we
+would add the void argument after the type argument giving us:
+
$sf :: forall t. Void# -> bla
$sf @t void = $se
RULE: f True = $sf void# (wrong)
-But if you look closely this wouldn't typecheck!
-If we substitute `f True` with `$sf void#` we expect the type argument to be applied first
-but we apply void# first.
-The easist fix seems to be just to add the void argument to the front of the arguments.
-Now we get:
+
+But if you look closely this wouldn't typecheck! If we substitute `f
+True` with `$sf void#` we expect the type argument to be applied first
+but we apply void# first. The easiest fix seems to be just to add the
+void argument to the front of the arguments. Now we get:
+
$sf :: Void# -> forall t. bla
$sf void @t = $se
RULE: f True = $sf void#
+
And now we can substitute `f True` with `$sf void#` with everything working out nicely!
+
+More precisely, in `calcSpecInfo`
+(i) we need the void arg to /precede/ the `extra_bndrs`, but
+(ii) it must still /follow/ `qvar_bndrs`.
+
+Example to illustrate (ii):
+ f :: forall r (a :: TYPE r). Bool -> a
+ f = /\r. /\(a::TYPE r). \b. body
+
+ {- Specialise for f _ _ True -}
+
+ $sf :: forall r (a :: TYPE r). Void# -> a
+ $sf = /\r. /\(a::TYPE r). \v. body[True/b]
+ RULE: forall r (a :: TYPE r). f @r @a True = $sf @r @a void#
+
+The void argument must follow the foralls, lest the forall be
+ill-kinded. See Note [Worker/wrapper needs to add void arg last] in
+GHC.Core.Opt.WorkWrap.Utils.
+
+Note [generaliseDictPats]
+~~~~~~~~~~~~~~~~~~~~~~~~~
+Consider these two rules (#21831, item 2):
+ RULE "SPEC:foo" forall d1 d2. foo @Int @Integer d1 d2 = $sfoo1
+ RULE "SC:foo" forall a. foo @Int @a $fNumInteger = $sfoo2 @a
+The former comes from the type class specialiser, the latter from SpecConstr.
+Note that $fNumInteger is a top-level binding for Num Integer.
+
+The trouble is that neither is more general than the other. In a call
+ (foo @Int @Integer $fNumInteger d)
+it isn't clear which rule to fire.
+
+The trouble is that the SpecConstr rule fires on a /specific/ dict, $fNumInteger,
+but actually /could/ fire regardless. That is, it could be
+ RULE "SC:foo" forall a d. foo @Int @a d = $sfoo2 @a
+
+Now, it is clear that SPEC:foo is more specific. But GHC can't tell
+that, because SpecConstr doesn't know that dictionary arguments are
+singleton types! So generaliseDictPats teaches it this fact. It
+spots such patterns (using typeDeterminesValue), and quantifies over
+the dictionary. Now we get
+
+ RULE "SC:foo" forall a d. foo @Int @a d = $sfoo2 @a
+
+And /now/ "SPEC:foo" is clearly more specific: we can instantiate the new
+"SC:foo" to match the (prefix of) "SPEC:foo".
-}
-calcSpecInfo :: Id -- The original function
- -> CallPat -- Call pattern
- -> [Var] -- Extra bndrs
- -> ( [Var] -- Demand-decorated binders
- , DmdSig -- Strictness of specialised thing
- , Arity, Maybe JoinArity ) -- Arities of specialised thing
--- Calcuate bits of IdInfo for the specialised function
+calcSpecInfo :: Id -- The original function
+ -> [InVar] -- Lambda binders of original RHS
+ -> CallPat -- Call pattern
+ -> [Var] -- Extra bndrs
+ -> ( [Var] -- Demand-decorated lambda binders
+ -- for RHS of specialised function
+ , [Var] -- Args for call site
+ , DmdSig ) -- Strictness of specialised thing
+-- Calculate bits of IdInfo for the specialised function
-- See Note [Transfer strictness]
-- See Note [Strictness information in worker binders]
-calcSpecInfo fn (CP { cp_qvars = qvars, cp_args = pats }) extra_bndrs
- | isJoinId fn -- Join points have strictness and arity for LHS only
- = ( bndrs_w_dmds
- , mkClosedDmdSig qvar_dmds div
- , count isId qvars
- , Just (length qvars) )
- | otherwise
- = ( bndrs_w_dmds
- , mkClosedDmdSig (qvar_dmds ++ extra_dmds) div
- , count isId qvars + count isId extra_bndrs
- , Nothing )
+calcSpecInfo fn arg_bndrs (CP { cp_qvars = qvars, cp_args = pats }) extra_bndrs
+ = ( spec_lam_bndrs_w_dmds
+ , spec_call_args
+ , mkClosedDmdSig [idDemandInfo b | b <- spec_lam_bndrs_w_dmds, isId b] div )
where
DmdSig (DmdType _ fn_dmds div) = idDmdSig fn
- val_pats = filterOut isTypeArg pats -- value args at call sites, used to determine how many demands to drop
- -- from the original functions demand and for setting up dmd_env.
+ val_pats = filterOut isTypeArg pats
+ -- Value args at call sites, used to determine how many demands to drop
+ -- from the original functions demand and for setting up dmd_env.
+ dmd_env = go emptyVarEnv fn_dmds val_pats
qvar_dmds = [ lookupVarEnv dmd_env qv `orElse` topDmd | qv <- qvars, isId qv ]
extra_dmds = dropList val_pats fn_dmds
- bndrs_w_dmds = set_dmds qvars qvar_dmds
- ++ set_dmds extra_bndrs extra_dmds
+ -- Annotate the variables with the strictness information from
+ -- the function (see Note [Strictness information in worker binders])
+ qvars_w_dmds = set_dmds qvars qvar_dmds
+ extras_w_dmds = set_dmds extra_bndrs extra_dmds
+ spec_lam_bndrs_w_dmds = final_qvars_w_dmds ++ extras_w_dmds
+
+ (final_qvars_w_dmds, spec_call_args)
+ | needsVoidWorkerArg fn arg_bndrs (qvars ++ extra_bndrs)
+ -- Usual w/w hack to avoid generating
+ -- a spec_rhs of unlifted or ill-kinded type and no args.
+ -- See Note [SpecConstr void argument insertion]
+ = ( qvars_w_dmds ++ [voidArgId], qvars ++ [voidPrimId] )
+ | otherwise
+ = ( qvars_w_dmds, qvars )
set_dmds :: [Var] -> [Demand] -> [Var]
set_dmds [] _ = []
@@ -1879,8 +1923,6 @@ calcSpecInfo fn (CP { cp_qvars = qvars, cp_args = pats }) extra_bndrs
set_dmds (v:vs) ds@(d:ds') | isTyVar v = v : set_dmds vs ds
| otherwise = setIdDemandInfo v d : set_dmds vs ds'
- dmd_env = go emptyVarEnv fn_dmds val_pats
-
go :: DmdEnv -> [Demand] -> [CoreExpr] -> DmdEnv
-- We've filtered out all the type patterns already
go env (d:ds) (pat : pats) = go (go_one env d pat) ds pats
@@ -1894,7 +1936,6 @@ calcSpecInfo fn (CP { cp_qvars = qvars, cp_args = pats }) extra_bndrs
= go env ds args
go_one env _ _ = env
-
{-
Note [spec_usg includes rhs_usg]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
=====================================
compiler/GHC/Core/Opt/WorkWrap/Utils.hs
=====================================
@@ -9,7 +9,7 @@ A library for the ``worker\/wrapper'' back-end to the strictness analyser
module GHC.Core.Opt.WorkWrap.Utils
( WwOpts(..), initWwOpts, mkWwBodies, mkWWstr, mkWWstr_one
- , needsVoidWorkerArg, addVoidWorkerArg
+ , needsVoidWorkerArg
, DataConPatContext(..)
, UnboxingDecision(..), wantToUnboxArg
, findTypeShape, IsRecDataConResult(..), isRecDataCon
@@ -387,25 +387,34 @@ We use the state-token type which generates no code.
-- Note [Preserving float barriers].
needsVoidWorkerArg :: Id -> [Var] -> [Var] -> Bool
needsVoidWorkerArg fn_id wrap_args work_args
- = not (isJoinId fn_id) && no_value_arg -- See Note [Protecting the last value argument]
- || needs_float_barrier -- See Note [Preserving float barriers]
+ = thunk_problem -- See Note [Protecting the last value argument]
+ || needs_float_barrier -- See Note [Preserving float barriers]
where
- no_value_arg = all (not . isId) work_args
+ -- thunk_problem: see Note [Protecting the last value argument]
+ -- For join points we are only worried about (4), not (1-4).
+ -- And (4) can't happen if (null work_args)
+ -- (We could be more clever, by looking at the result type, but
+ -- this approach is simple and conservative.)
+ thunk_problem | isJoinId fn_id = no_value_arg && not (null work_args)
+ | otherwise = no_value_arg
+ no_value_arg = not (any isId work_args)
+
+ -- needs_float_barrier: see Note [Preserving float barriers]
+ needs_float_barrier = wrap_had_barrier && not work_has_barrier
is_float_barrier v = isId v && hasNoOneShotInfo (idOneShotInfo v)
wrap_had_barrier = any is_float_barrier wrap_args
work_has_barrier = any is_float_barrier work_args
- needs_float_barrier = wrap_had_barrier && not work_has_barrier
--- | Inserts a `Void#` arg before the first argument.
---
--- Why as the first argument? See Note [SpecConst needs to add void args first]
--- in SpecConstr.
+-- | Inserts a `Void#` arg as the last argument.
+-- Why last? See Note [Worker/wrapper needs to add void arg last]
addVoidWorkerArg :: [Var] -> [StrictnessMark]
- -> ([Var], -- Lambda bound args
- [Var], -- Args at call site
- [StrictnessMark]) -- cbv semantics for the worker args.
-addVoidWorkerArg work_args cbv_marks
- = (voidArgId : work_args, voidPrimId:work_args, NotMarkedStrict:cbv_marks)
+ -> ( [Var] -- Lambda bound args
+ , [Var] -- Args at call site
+ , [StrictnessMark]) -- str semantics for the worker args
+addVoidWorkerArg work_args str_marks
+ = ( work_args ++ [voidArgId]
+ , work_args ++ [voidPrimId]
+ , str_marks ++ [NotMarkedStrict] )
{-
Note [Protecting the last value argument]
@@ -413,8 +422,8 @@ Note [Protecting the last value argument]
If the user writes (\_ -> E), they might be intentionally disallowing
the sharing of E. Since absence analysis and worker-wrapper are keen
to remove such unused arguments, we add in a void argument to prevent
-the function from becoming a thunk. Three reasons why turning a function
-into a thunk might be bad:
+the function from becoming a thunk. Here are several reasons why turning
+a function into a thunk might be bad:
1) It can create a space leak. e.g.
f x = let y () = [1..x]
@@ -433,7 +442,19 @@ into a thunk might be bad:
g = \x. 30#
Removing the \x would leave an unlifted binding.
-NB: none of these apply to a join point.
+4) It can create a worker of ill-kinded type (#22275). Consider
+ f :: forall r (a :: TYPE r). () -> a
+ f x = f x
+ Here `x` is absent, but if we simply drop it we'd end up with
+ $wf :: forall r (a :: TYPE r). a
+ But alas $wf's type is ill-kinded: the kind of (/\r (a::TYPE r).a)
+ is (TYPE r), which mentions the bound variable `r`. See also
+ Note [Worker/wrapper needs to add void arg last]
+
+See also Note [Preserving float barriers]
+
+NB: Of these, only (1-3) don't apply to a join point, which can be
+unlifted even if the RHS is not ok-for-speculation.
Note [Preserving float barriers]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -467,7 +488,7 @@ which some are absent or one-shot and the resulting worker arguments:
* \a{Abs}.\b{os}.\c{os}... ==> \b{os}.\c{os}.\(_::Void#)...
Wrapper arg `a` was the only float barrier and had been dropped. Hence Void#
- * \a{Abs,os}.\b{os}.\c... ==> \b{os}.\c...
+p * \a{Abs,os}.\b{os}.\c... ==> \b{os}.\c...
Worker arg `c` is a float barrier.
* \a.\b{Abs}.\c{os}... ==> \a.\c{os}...
Worker arg `a` is a float barrier.
@@ -479,6 +500,27 @@ which some are absent or one-shot and the resulting worker arguments:
Executable examples in T21150.
+Note [Worker/wrapper needs to add void arg last]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Consider point (4) of Note [Protecting the last value argument]
+
+ f :: forall r (a :: TYPE r). () -> a
+ f x = f x
+
+As pointed out in (4) we need to add a void argument. But if we add
+it /first/ we'd get
+
+ $wf :: Void# -> forall r (a :: TYPE r). a
+ $wf = ...
+
+But alas $wf's type is /still/ still-kinded, just as before in (4).
+Solution is simple: put the void argument /last/:
+
+ $wf :: forall r (a :: TYPE r). Void# -> a
+ $wf = ...
+
+c.f Note [SpecConstr void argument insertion] in GHC.Core.Opt.SpecConstr
+
Note [Join points and beta-redexes]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Originally, the worker would invoke the original function by calling it with
=====================================
compiler/GHC/Core/Utils.hs
=====================================
@@ -166,7 +166,7 @@ coreAltsType :: [CoreAlt] -> Type
coreAltsType (alt:_) = coreAltType alt
coreAltsType [] = panic "coreAltsType"
-mkLamType :: Var -> Type -> Type
+mkLamType :: HasDebugCallStack => Var -> Type -> Type
-- ^ Makes a @(->)@ type or an implicit forall type, depending
-- on whether it is given a type variable or a term variable.
-- This is used, for example, when producing the type of a lambda.
=====================================
testsuite/tests/simplCore/should_compile/T13143.stderr
=====================================
@@ -1,14 +1,14 @@
==================== Tidy Core ====================
Result size of Tidy Core
- = {terms: 71, types: 41, coercions: 0, joins: 0/0}
+ = {terms: 71, types: 40, coercions: 0, joins: 0/0}
Rec {
-- RHS size: {terms: 4, types: 3, coercions: 0, joins: 0/0}
T13143.$wf [InlPrag=NOINLINE, Occ=LoopBreaker]
- :: (# #) -> forall {a}. a
+ :: forall {a}. (# #) -> a
[GblId, Arity=1, Str=<B>b, Cpr=b, Unf=OtherCon []]
-T13143.$wf = \ _ [Occ=Dead] (@a) -> T13143.$wf GHC.Prim.(##) @a
+T13143.$wf = \ (@a) _ [Occ=Dead] -> T13143.$wf @a GHC.Prim.(##)
end Rec }
-- RHS size: {terms: 4, types: 3, coercions: 0, joins: 0/0}
@@ -20,8 +20,8 @@ f [InlPrag=[final]] :: forall a. Int -> a
Unf=Unf{Src=InlineStable, TopLvl=True, Value=True, ConLike=True,
WorkFree=True, Expandable=True,
Guidance=ALWAYS_IF(arity=1,unsat_ok=True,boring_ok=True)
- Tmpl= \ (@a) _ [Occ=Dead] -> T13143.$wf GHC.Prim.(##) @a}]
-f = \ (@a) _ [Occ=Dead] -> T13143.$wf GHC.Prim.(##) @a
+ Tmpl= \ (@a) _ [Occ=Dead] -> T13143.$wf @a GHC.Prim.(##)}]
+f = \ (@a) _ [Occ=Dead] -> T13143.$wf @a GHC.Prim.(##)
-- RHS size: {terms: 1, types: 0, coercions: 0, joins: 0/0}
T13143.$trModule4 :: GHC.Prim.Addr#
@@ -59,13 +59,13 @@ T13143.$trModule :: GHC.Types.Module
T13143.$trModule
= GHC.Types.Module T13143.$trModule3 T13143.$trModule1
--- RHS size: {terms: 2, types: 0, coercions: 0, joins: 0/0}
-lvl :: forall {a}. a
+-- RHS size: {terms: 2, types: 1, coercions: 0, joins: 0/0}
+lvl :: Int
[GblId, Str=b, Cpr=b]
-lvl = T13143.$wf GHC.Prim.(##)
+lvl = T13143.$wf @Int GHC.Prim.(##)
Rec {
--- RHS size: {terms: 28, types: 8, coercions: 0, joins: 0/0}
+-- RHS size: {terms: 28, types: 7, coercions: 0, joins: 0/0}
T13143.$wg [InlPrag=[2], Occ=LoopBreaker]
:: Bool -> Bool -> GHC.Prim.Int# -> GHC.Prim.Int#
[GblId[StrictWorker([!, !])],
=====================================
testsuite/tests/simplCore/should_compile/T18328.stderr
=====================================
@@ -1,84 +1,90 @@
==================== Tidy Core ====================
Result size of Tidy Core
- = {terms: 65, types: 53, coercions: 0, joins: 1/1}
+ = {terms: 69, types: 55, coercions: 0, joins: 1/1}
--- RHS size: {terms: 38, types: 23, coercions: 0, joins: 1/1}
+-- RHS size: {terms: 42, types: 25, coercions: 0, joins: 1/1}
T18328.$wf [InlPrag=[2]]
:: forall {a}. GHC.Prim.Int# -> [a] -> [a] -> [a]
-[GblId,
+[GblId[StrictWorker([~, !])],
Arity=3,
Str=<SL><SL><ML>,
- Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True,
- WorkFree=True, Expandable=True, Guidance=IF_ARGS [176 0 0] 306 0}]
+ Unf=Unf{Src=<vanilla>, TopLvl=True,
+ Value=True, ConLike=True, WorkFree=True, Expandable=True,
+ Guidance=IF_ARGS [176 0 0] 306 0}]
T18328.$wf
- = \ (@a) (ww :: GHC.Prim.Int#) (w :: [a]) (w1 :: [a]) ->
+ = \ (@a) (ww :: GHC.Prim.Int#) (ys :: [a]) (eta :: [a]) ->
join {
- $wj [InlPrag=NOINLINE, Dmd=ML] :: forall {p}. [a]
- [LclId[JoinId(1)]]
- $wj (@p)
+ $wj [InlPrag=NOINLINE, Dmd=MC(1,L)] :: forall {p}. (# #) -> [a]
+ [LclId[JoinId(2)(Nothing)], Arity=1, Str=<A>, Unf=OtherCon []]
+ $wj (@p) _ [Occ=Dead, OS=OneShot]
= case ww of {
- __DEFAULT -> ++ @a w (++ @a w (++ @a w w1));
- 3# -> ++ @a w (++ @a w (++ @a w (++ @a w w1)))
+ __DEFAULT -> ++ @a ys (++ @a ys (++ @a ys eta));
+ 3# -> ++ @a ys (++ @a ys (++ @a ys (++ @a ys eta)))
} } in
case ww of {
- __DEFAULT -> ++ @a w w1;
- 1# -> jump $wj @Integer;
- 2# -> jump $wj @Integer;
- 3# -> jump $wj @Integer
+ __DEFAULT -> ++ @a ys eta;
+ 1# -> jump $wj @Integer GHC.Prim.(##);
+ 2# -> jump $wj @Integer GHC.Prim.(##);
+ 3# -> jump $wj @Integer GHC.Prim.(##)
}
-- RHS size: {terms: 11, types: 9, coercions: 0, joins: 0/0}
f [InlPrag=[2]] :: forall a. Int -> [a] -> [a] -> [a]
[GblId,
Arity=3,
- Str=<1P(SL)><SL><ML>,
- Unf=Unf{Src=InlineStable, TopLvl=True, Value=True, ConLike=True,
- WorkFree=True, Expandable=True,
+ Str=<1!P(SL)><SL><ML>,
+ Unf=Unf{Src=StableSystem, TopLvl=True,
+ Value=True, ConLike=True, WorkFree=True, Expandable=True,
Guidance=ALWAYS_IF(arity=3,unsat_ok=True,boring_ok=False)
Tmpl= \ (@a)
- (w [Occ=Once1!] :: Int)
- (w1 [Occ=Once1] :: [a])
- (w2 [Occ=Once1] :: [a]) ->
- case w of { GHC.Types.I# ww [Occ=Once1] ->
- T18328.$wf @a ww w1 w2
+ (x [Occ=Once1!] :: Int)
+ (ys [Occ=Once1] :: [a])
+ (eta [Occ=Once1] :: [a]) ->
+ case x of { GHC.Types.I# ww [Occ=Once1] ->
+ T18328.$wf @a ww ys eta
}}]
-f = \ (@a) (w :: Int) (w1 :: [a]) (w2 :: [a]) ->
- case w of { GHC.Types.I# ww -> T18328.$wf @a ww w1 w2 }
+f = \ (@a) (x :: Int) (ys :: [a]) (eta :: [a]) ->
+ case x of { GHC.Types.I# ww -> T18328.$wf @a ww ys eta }
-- RHS size: {terms: 1, types: 0, coercions: 0, joins: 0/0}
T18328.$trModule4 :: GHC.Prim.Addr#
[GblId,
- Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True,
- WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 20 0}]
+ Unf=Unf{Src=<vanilla>, TopLvl=True,
+ Value=True, ConLike=True, WorkFree=True, Expandable=True,
+ Guidance=IF_ARGS [] 20 0}]
T18328.$trModule4 = "main"#
-- RHS size: {terms: 2, types: 0, coercions: 0, joins: 0/0}
T18328.$trModule3 :: GHC.Types.TrName
[GblId,
- Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True,
- WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 10 10}]
+ Unf=Unf{Src=<vanilla>, TopLvl=True,
+ Value=True, ConLike=True, WorkFree=True, Expandable=True,
+ Guidance=IF_ARGS [] 10 10}]
T18328.$trModule3 = GHC.Types.TrNameS T18328.$trModule4
-- RHS size: {terms: 1, types: 0, coercions: 0, joins: 0/0}
T18328.$trModule2 :: GHC.Prim.Addr#
[GblId,
- Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True,
- WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 30 0}]
+ Unf=Unf{Src=<vanilla>, TopLvl=True,
+ Value=True, ConLike=True, WorkFree=True, Expandable=True,
+ Guidance=IF_ARGS [] 30 0}]
T18328.$trModule2 = "T18328"#
-- RHS size: {terms: 2, types: 0, coercions: 0, joins: 0/0}
T18328.$trModule1 :: GHC.Types.TrName
[GblId,
- Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True,
- WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 10 10}]
+ Unf=Unf{Src=<vanilla>, TopLvl=True,
+ Value=True, ConLike=True, WorkFree=True, Expandable=True,
+ Guidance=IF_ARGS [] 10 10}]
T18328.$trModule1 = GHC.Types.TrNameS T18328.$trModule2
-- RHS size: {terms: 3, types: 0, coercions: 0, joins: 0/0}
T18328.$trModule :: GHC.Types.Module
[GblId,
- Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True,
- WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 10 10}]
+ Unf=Unf{Src=<vanilla>, TopLvl=True,
+ Value=True, ConLike=True, WorkFree=True, Expandable=True,
+ Guidance=IF_ARGS [] 10 10}]
T18328.$trModule
= GHC.Types.Module T18328.$trModule3 T18328.$trModule1
=====================================
testsuite/tests/simplCore/should_compile/T22725.hs
=====================================
@@ -0,0 +1,6 @@
+module M where
+
+import GHC.Exts (TYPE)
+
+f :: forall r (a :: TYPE r). () -> a
+f x = f x
=====================================
testsuite/tests/simplCore/should_compile/all.T
=====================================
@@ -398,3 +398,4 @@ test('T22112', normal, compile, ['-O -dsuppress-uniques -dno-typeable-binds -ddu
test('T22491', normal, compile, ['-O2'])
test('T22623', normal, multimod_compile, ['T22623', '-O -v0'])
test('T22662', normal, compile, [''])
+test('T22725', normal, compile, ['-O'])
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/aad62f1f11679d875705a0d9b86fbc9552e336cc
--
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/aad62f1f11679d875705a0d9b86fbc9552e336cc
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